Real-time shape approximation and fingerprinting of single proteins using a nanopore

Abstract

Established methods for characterizing proteins typically require physical or chemical modification steps or cannot be used to examine individual molecules in solution. Ionic current measurements through electrolyte-filled nanopores can characterize single native proteins in an aqueous environment, but currently offer only limited capabilities. Here we show that the zeptolitre sensing volume of bilayer-coated solid-state nanopores can be used to determine the approximate shape, volume, charge, rotational diffusion coefficient and dipole moment of individual proteins. To do this, we developed a theory for the quantitative understanding of modulations in ionic current that arise from the rotational dynamics of single proteins as they move through the electric field inside the nanopore. The approach allows us to measure the five parameters simultaneously, and we show that they can be used to identify, characterize and quantify proteins and protein complexes with potential implications for structural biology, proteomics, biomarker detection and routine protein analysis.

It's Not a Bug, It's a Feature: Functional Materials in Insects

“…Recent research from our group has taken inspiration from the lipid-bilayer-lined pores in the walls of sensilla in moth antennae, which also have the function of detecting and identifying chemicals in small amounts. Moth sensilla provide a nonstick fluid coating ( Figure 19C, [430][431][432] ) and selective odorant-binding proteins and neural receptors enable moths to distinguish between odorants as described below. [430,[433][434][435] Similarly, selective conjugation of an analyte to a lipid membrane imparts selectivity to synthetic nanopore systems while minimizing nonspecific adsorption.…”

“…[430,[433][434][435] Similarly, selective conjugation of an analyte to a lipid membrane imparts selectivity to synthetic nanopore systems while minimizing nonspecific adsorption. [431,432] By convention, an insect recognizes airborne chemicals by smelling them (olfaction), while it recognizes aqueous chemicals by tasting them (gustation). The mechanism for both modes of sensing is, however, nearly identical.…”

“…[2] Detection systems with this sensitivity threshold are clearly attractive for engineered sensors, especially those designed to characterize challenging analytes such as, for instance, amyloid-beta, a peptide that has implications in Alzheimer's disease and forms transient, heterogeneous aggregates that tend to stick to surfaces. [431,432] …”

Membrane protein-based biosensors

“…For larger size analytes such as proteins, Mayer and colleagues developed a solid-state nanopore with a size of few tens of a nanometre, coated with a lipid bilayer on its surface [88]. The analyte proteins were tagged to the lipid bilayer, delivered to the pore, and their shapes and volumes were characterized [89]. We consider that these highlighted studies on various materials would lead to tailor-made nanopores for a broad range of sensing targets.…”

Deployment and exploitation of nanotechnology nanomaterials and nanomedicine

“…However, questions on its accuracy have been raised. Nanopore technology is also being developed for sensing proteins and small analytes [106,107]. Nanotechnologies for in vivo diagnostics and therapeutics -The materials and technologies required for in vivo applications are more constrained than ex-vivo.…”